In what could go down as one of its most notable reckonings of the era, the Supreme Court will hear arguments next week in two major gay marriage cases. As the advocates and justices prepare to spar over California's Proposition 8 and the federal Defense of Marriage Act, important constitutional principles are heading toward a much-needed day in the sun.

As are some crucial but underappreciated subplots in this whole story about gay rights in America: the degree to which specific religious teachings — such as Thou Shalt Not Be Gay — should be enshrined as the law of the land, and the underlying question about the proper relationship between government and religion.

The moment is ripe for religious Americans, especially those Christian conservatives who have led the resistance against gay rights, to remember the importance of keeping church and state independent of one another. "Secularism" is not the church person's bane as it's often made out to be but the best protection ever devised for religious freedom. Let's hope this principle makes it through this major test intact and healthy.

Certainly, the same-sex marriage cases are about more than religion. But much of the energy fueling the traditional marriage movement is religious. After the announcement by Sen. Rob Portman, R-Ohio, that he's now supporting gay marriage, Newt Gingrich spoke for many Christian conservatives when he said, "I don't think (politicians) have the power to change what is a religiously inspired definition" of marriage. Gingrich and like-minded religious people are entitled to believe this, of course. But that doesn't mean the government should translate this religious belief into the law.

In this time of polarized shouting matches, the public square has fallen for distorted understanding of the terms "secularism" and "religious freedom." Judging from the popular (mis)understanding and rhetoric, secularists and religious freedom enthusiasts are archenemies, not allies.

Leave it to a secular Jew on the faculty of a Catholic university to set us straight. As Georgetown's Jacques Berlinerblau argues in How to Be Secular, we should stop allowing the strident shouters on the extreme ends of the spectrum to misrepresent the crucial religious freedom issues.

Properly understood, secularism is not about total godlessness or an absolute separation of religion from government. It is, more precisely, a model of church and state in which government is not under the control of a church authority, and no churches or individuals are having their religious practice and beliefs, or non-belief, dictated by the government. This is why secularists and religious freedom champions owe each other appreciation, not scorn.

It's not just the Bible-based arguments against same-sex marriage that violate this healthy secularism, unfortunately. Berlinerblau urges his fellow secularists to abandon the notion that secularism equals atheism. Cross-shaped memorials on public land, non-denominational prayers at public events — do these displays of faith all have to be fought as some non-believers seem to think? Do we have to deny God and religion to stand up for secularism? No, we don't, Berlinerblau asserts.

Even the most vigorous religionists have reason to appreciate secularism and its vigilance against unhealthy church-state entanglements. These days, Baptists are a big part of the evangelical constituency, which often leads the charge against secularism. But it was the Baptists who often stood hardest against church-state entanglements in the nation's early days, when establishment of an official national religion was a real and present danger to them and other religious minorities. Today, if Baptists and other evangelicals want to be free of worries about an officially Catholic, or Muslim, or humanist government someday dictating their belief, they ought to invest in religious freedom's sturdiest bulwark: secularism.

More than their shared passions about church-state relationships, the ardent secularists and religious freedom champions have common cause, too: their mutual interest in keeping churches and consciences free of government control, and government free of church control.

If ever two warring parties were allies in disguise, it's these. And that will remain true whichever way the Supreme Court comes down on the big gay marriage cases.

Tom Krattenmaker is a Portland-based writer specializing in religion in public life and a member of USA TODAY's Board of Contributors. His book The Evangelicals You Don't Know will be released in April.